Biosynthetic Collagen-Analog Hydrogels Stimulate Endogenous Regrowth of Rabbit Corneas: A Pilot Study

Pro-regenerative corneal implants are being developed to improve corneal healing for companion animals in clinical practice. This pilot study evaluated early corneal tissue and nerve regeneration using biosynthetic collagen-analog hydrogels (CAH) in liquid and solid forms. Their efficacy was compared to each other and to allografts on nine white New Zealand rabbits, divided in three groups of three. Each rabbit cornea underwent keratectomy followed by grafting with either a control allograft cornea, liquid injectable, or solid CAH implant. Corneal healing was assessed over 16 weeks using clinical exams, esthesiometry, in vivo confocal microscopy, and optical coherence tomography. One rabbit per group was euthanized at 3, 10, and 16 weeks for histopathological analysis. Both liquid and solid implants enabled corneal re-epithelialization and regeneration of stromal tissue and corneal nerves. Esthesiometric values indicated faster nerve regeneration in rabbits grafted with biosynthetic implants compared to allografts (p < 0.005). By 16 weeks, regenerated neocorneas achieved transparency comparable to allografts. Solid and liquid CAH implants supported complete corneal tissue and nerve regeneration in the studied rabbits. These results suggest that with further research and development, the current gold standard for corneal transplantation could be replaced by high-performing, easily produced biosynthetic alternatives.